In the control of compression-ignition internal combustion, or diesel engines, the conventional practice utilizes electronic control units having volatile and nonvolatile memory, input and output driver circuitry, and a processor capable of executing a stored instruction set, to control the various functions of the engine and its associated systems. A particular electronic control unit communicates with a plethora of sensors, actuators, and, sometimes, other electronic control units necessary to control various functions which may include fuel delivery, cooling fan control, engine speed governing and overspeed protection, engine braking, torque control, vehicle speed control, or myriad others. One such method and apparatus for comprehensive integrated engine control is disclosed in U.S. Pat. No. 5,445,128, issued Aug. 29, 1995 to Letang et al for "Method For Engine Control" and assigned to Detroit Diesel Corporation, assignee of the present invention.
One type of engine method and system for obtaining a braking effect on an internal combustion engine involves converting the engine into an air compressor; i.e., by opening a valve to the atmosphere near the end of the compression stroke and closing it shortly afterwards. The momentum of the moving vehicle can be retarded utilizing this system, which is commonly referred to as a "Jake Brake". One such conventional engine braking system is available from Jacobs Manufacturing Company, of Wilmington, Del.
It is also known to utilize an electronic engine control to automatically stop and start an engine in response to selected conditions which are monitored by the engine control system, such as air temperature. PCT Publication No. WO 95/31638, published Nov. 23, 1995 discloses an engine control including such automatic engine shutdown and startup capabilities.
One problem encountered in the implementation of automatic engine shutdown features is an annoying vibration of the cab.
It is therefore desirable to provide a method and system for reducing cab vibration during engine shutdown which may be automatically implemented by electronic engine control units.